Electronic Apex Locator — NDEB AFK MCQ
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Correct answer: E — Electronic apex locator (EAL)
Electronic apex locators (EALs, e.g., Root ZX, Apex ID) provide the most accurate determination of working length by measuring changes in electrical impedance or resistance as the file approaches the apical constriction. Third-generation (ratio-type) and later EALs have accuracy rates of 90-96.5% within ±0.5 mm of the apical constriction. They are more accurate than radiographic methods, which are subject to distortion, superimposition, and the discrepancy between radiographic apex and apical constriction.
Reference: Torabinejad – Endodontics: Principles and Practice, 6th ed., 2021